Your new pursuit camera attempts are good -- especially a few frames in the second video have very good freezeframes -- that said, it looks even better when
1. I load the YouTube fullscreen
2. Then switch YouTube quality to 1080p 60fps, and play through twice,
3. Then slide the slider and press pause when close to best freeze frame
4. Then use the period/comma "," and "." keys to single-frame step backwards and forwards
5. Then screenshot the sharpest ladder frame (fewest sync track distortions).
And voila, the 120Hz and the 240Hz ones.
120Hz
240Hz
(Ignoring the screen reflection in the middle, you did a great job of video pursuit on this one, this time around!)
Still a smidge overexposed (alien eyes are washed out, yellow dome is whitish-yellow), so you may need to decrease the camera ISO without changing exposure length, and/or reduce the brightness of the monitor. Maybe slightly adjust focus a bit better (Fixed focus), but it's sometimes hard to get good focus for a hand-wave without a rail.
But this one is a MUCH better pursuit camera attempt -- good job.
Now cropping a zoomed portion of your best freezeframe, 120Hz vs 240Hz:
vs
(That's a very great second-attempt job for a rail-less hand-wave smartphone pursuit -- even despite compression artifact -- slight overexposure -- and slight unfocus -- and the viewing-angle-issue amplification caused by smartphone closer to screen than human eyes -- which caused the middle and bottom bars to gain the same cyan tint. Despite these minor flaws, I'm able to now able to 'confidently' analyze these photos since it more accurately captured strobe crosstalk).
Note: No need to re-attempt these particulars but to give helpful pursuit camera tips -- for future monitors or future hobby pursuit camera, try testing a pre-focus to fixed focus, also try further away (phone lens same distance as regular eye viewing distance) and instead zooming in to prevent viewing-angle amplification artifact (but that can kill smartphone camera resolution, so tradeoff, if no optical zoom), slightly lower ISO number to darken the photo or dim monitor brightness, and if phone allows, use the highest possible bitrate to minimize compression artifacts. Also, if your video app is limiting, try a different app -- though sometimes some adjustments are impossible on some models of smartphones, unfortunately.
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Now for my honest commentary on this;
-- This is better than the 240Hz IPS monitors on IPS strobe crosstalk.
-- This is average for TN strobe crosstalk at 240Hz. XG270 more crosstalk at 240Hz. (XG270 180Hz-230Hz gets close, tho).
-- This is average for TN strobe crosstalk at 120Hz. XG270 less crosstalk at 120Hz. (Yes, IPS strobing better than TN!)
-- 240Hz is not too distracting if your priority is low-lag strobing over low-crosstalk strobing
That said, where XG270 will shine, is strobing at 120Hz (make sure to install Viewsonic Elite Display Controller in order to automatically receive the newly-released firmware upgrade for brighter strobing -- then you have multiple PureXP brightness options). So make sure you test PureXP at its recommended refresh rates (even though it's not strobe-Hz locked like some strobe brands such as ULMB).